Printing inks containing styrenemaleic anhydride copolymer and carbon black



Unite Sit res Patented Sept. 11, 1962 New Jersey No Drawing. Filed Aug. 17, 1959, Ser. No. 833,957 2 Claims. (Cl. 260-175) This invention relates to a printing ink and more particularly to an improved printing ink which is suitable for use on photographic film backing paper.

Photographic backing paper which is presently employed with roll film comprises a strip of paper having various protective light colored and opaquing coatings thereon. Photographic paper of this kind is described in U.S. Patent 2,751,309 of June 19, 1956. A typical backing paper structure comprises a strip of unbleached kraft paper having on one side a layer of carbon black in a vinylidene chloride-acrylonitrile copolymer. On the opposite side of the kraft paper there is a yellow coating comprising chrome orange and yellow pigments as well as titanium dioxide pigments in a zein binder. The printed indicia is printed onto the above-described yellow coating and the printing is overcoated with a transparent protective coating of zein. The transparent zein protective coating is described in U.S. Patent 2,262,987 of Nov. 18, 1941.

The printing ink preferably employed, up to the instant invention, on the backing paper described in Patent 2,751,309 is that described in U.S. Patent Re. 21,268 of Nov. 21, 1939. This ink comprises suitable organic coloring materials in a prolamine binder such as zein in alcoholic solution.

It has been noted from time to time that this ink, described in Re. 21,268, had a tendency to smear when overcoated with the clear zein coating. Furthermore, it is desirable that the printed indicia be visible under the infrared light employed when inspecting the roll film and the ink described in Re. 21,268 does not have this desirable property.

An object of this invention is to provide an improved printing ink suitable for use on the type of photographic film backing paper described in Patent 2,751,309 which is photographically inactive, is visible under infrared light and which does not smear when an alcoholic zein protective layer is coated over the printing.

In accordance with the present invention, these and other objects are attained by employing a printing ink of the following composition:

Percent Carbon Black (Raven Beads) 5.05 Carbon Black (Statex 93 Beads) 5.05

Carbon Black Dispersing Agent (Marasperse CB) Sodium Hydroxide Percent Ammonium Hydroxide 1.15 Styrene-Maleic Anhydride Copolymer (Scriptite 54) 3.73 Water 50.33 Ethyl Alcohol 33.90

The above formulation represents a preferred embodiment of the present invention. I have found, however, a satisfactory ink can be produced when certain variations are made. The carbon black content may b varied within the range of 5 to 15%. The styrene-maleic anhydride content may be varied within the range of 3 to 5%, the water from 40 to and the ethyl alcohol from 30 to 60%. The several ingredients are stirred until a substantially homogeneous mixture is achieved. The ink may be applied to the backing paper by rotogravure processes.

As indicated in the above formulation, the preferred carbon blacks employed are those sold under the trademarks Statex 93 and Raven Beads. The preferred styrene-maleic anhydride copolymer is that sold under the trademark Scriptite 54. U.S. Patent 2,047,398 of July 14, 1936 also discloses suitable styrene-maleic anhydride copolymers which are usable in my ink formulation. The preferred dispersing agent is that sold under the trademark Marasperse CB which is a highly puritied, partially desulfonated sodium lignosulfonate.

Accelerated tests and prolonged keeping tests indicated that this printing ink shows no photographic activity. The ink produces sharp black printing. It shows up readily under infrared inspection and may also be employed for photoelectric pick-up on the automatic spooling machines for controlling the length and placement of film. The ink also does not smear when it comes in contact with an alcoholic zein solution.

I claim:

1. A printing ink comprising from 515% carbon black, from 3-5 of styrene-maleic anhydride copolymer, from 30-60% ethyl alcohol, from 40-60% water, 0.74% partially 'desulfonated sodium lignosulfonate dispersing agent, 0.05% sodium hydroxide, and 1.15% ammonium hydroxide.

2. A printing ink consisting of 10.1% carbon black, 0.74% partially desulfonated sodium lignosulfonate dispersing agent, 0.05% sodium hydroxide, 1.5% ammonium hydroxide, 3.73% styrene-maleic anhydride copolymer, 33.09% ethyl alcohol, and 50.33% water.

References Cited in the file of this patent UNITED STATES PATENTS 2,236,521 Coleman Apr. 1, 1941 2,607,762 Bowen Aug. 19, 1952 2,868,757 Symons Jan. 13, 1959 2,904,523 Hawkins Sept. 15, 1959 2,930,775 Fordyce et a1. Mar. 29, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,053,779 September 11, 1962 William O. ONeill It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 48, for "33.09%" read 33.90%

Signed and sealed this 5th day of March 1963.

(SEAL) Attest:

ESTON G. JOHNSON DAVID L. LADD Attesting Officer Commissioner of Patents 

1. A PRINTING INK COMPRISING FROM 5-15% CARBON BLACK, FROM 3-5% OF STYRENE-MALEIC ANHYDRIDE COPOLYMER, FROM 30-60% ETHYL ALCOHOL, FROM 40-60% WATER, 0.74% PARTIALLY SESULFONATED SODIUM LIGNOSULFONATE DISPERSING AGENT, 0.05% SODIUM HYDROXIDE, AND 1.15% AMMONIUM HYDROXIDE. 